Efeito das diferenças sexuais e da capacidade aeróbica na resposta sudorípara de homens e mulheres

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Human capacity to dissipate heat in hot environments depends mainly on sweat secretion and evaporation. Studies have shown that men have greater sweating capacity and produce more sweat in response to similar stimulation than women. However, due to sexual dimorphism and typical differences in VO2máx, it is not known yet if sudorific differences are really sex-related. Besides, it is not clear if these differences are given by variations in central stimulation or in peripheral sweating response. Therefore, the purpose of this study was to compare sudorific activity during graded exercise until exhaustion (EP) and to verify if there are differences in sweat cholinergic sensitivity and capacity between men and women. It was studied 44 subjects subdivided in four groups: males with greater (GM>) and lesser (GM<) VO2máx and females with greater (GF>) and lesser (GF<) VO2máx. They participated in two experimental situations: EP and local sweat induction through pilocarpine iontophoresis (1.5 mA; 5 min) in six concentrations (PILO). It was measured total sweat rate (TStotal, g.m-2.min-1), local sweat rate (TSlocal, g.m-2.min-1) and number of active sweat glands (GSA, glândulas. cm-2). Males groups had greater mass (GM>= 71.25 ± 11.62; GM<= 73.91 ± 5.69; GF>= 56.73 ± 5.67 e GF<= 55.33 ± 3.15 kg) and height (GM>= 176 ± 7.97; GM<= 173 ± 3.75; GF>= 164 ± 5.75 e GF<= 161 ± 6.93 cm) but smaller BSA to mass ratio than females (GM>= 0.026 ± 0.002; GM<= 0.026 ± 0.001; GF>= 0.029 ± 0.001 e GF<= 0.029 ± 0.001 m².kg-1). During EP, VO2máx (mL.kg-1.min-1) was higher in GM>(47 ± 6.19), similar in GM<(37 ± 4.81) and GF>(40 ± 3.86) and smaller in GF<(32 ± 3.38). XTStotal was greater in GM>(3.66 ± 0.76), similar in GM<(2.85 ± 1.00) and GF>(2.55 ± 0.44) and smaller in GF<(1.69 ± 0.56), just as VO2máx. However, TSlocal was different among groups (GM>= 9.007 ± 5.900; GM<= 7.002 ± 5.560; GF>= 3.433 ± 1.521 e GF<= 1.665 ± 1.069). During PILO, sweating dose-response curves were different among groups. Maximal TSlocal was greater in GM>(8.165 ± 3.652), similar in GM<(5.794 ± 3.812) and GF>(5.585 ± 1.852) and smaller in GF<(3.179 ± 0.769). Nevertheless, GM>and GF>increased sweat rates until concentration of 1.0%, while GM

ASSUNTO(S)

caracteres sexuais decs corpo temperatura regulação. teses sudorese decs exercícios físicos aspectos fisiológicos teses

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